Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds meaningful behavioral context beyond the annotations: the view change affects 'everyone's view,' coordinates are scene pixels rather than grid squares, and omitted fields preserve current settings. It also reveals the animation mechanism via canvas.animatePan. This is more than the annotations alone convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with no filler. The primary action and key constraints are front-loaded, the coordinate system clarification is prominent, and the sibling alternative is a single clear sentence at the end.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple, fully-optional-parameter tool with no output schema, the description covers everything needed to invoke it correctly: action, coordinate system, optionality, effect scope, and the alternative sibling. No important gap remains.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already documents each parameter with 100% coverage, so the bar is lower, but the description still adds value by emphasizing 'scene pixels, not grid squares' and explicitly stating that all fields are optional. This reinforces the coordinate system and partial-update semantics beyond the individual parameter descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: 'Pan and/or zoom the canvas to scene-pixel coordinates' and names the underlying API method. It clearly distinguishes this from canvas-ping by stating the different purpose and explicitly naming the sibling.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides explicit guidance on when to use this tool versus the alternative: 'Use canvas-ping to draw attention to a spot instead.' It also clarifies field optionality so an agent knows it can partially update the view without supplying all parameters.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.